A method and apparatus for estimating the value of a slider airbearing resonance frequency involves obtaining a readback signal from a data storage medium over a plurality of complete airbearing periods and estimating the value of an airbearing resonance frequency using the readback signal. In one embodiment, a discrete signal segment comprising a plurality of frequency transform components is produced using the readback signal information, and the value of the airbearing resonance frequency is estimated using spectral leakage in the discrete signal segment. A ratio of the magnitudes of a first DFT component to a second DFT component is computed at each of a plurality of sampling rates. Each of these sampling rates is defined by a number of samples per average airbearing cycle multiplied by a frequency falling within a range of expected airbearing frequencies associated with a given implementation. The second DFT component is related to the slider airbearing resonance frequency, and the first DFT component is a DFT component adjacent to or non-adjacent to the second DFT component. The airbearing resonance frequency value is estimated using a minimum of the ratios, which may also constitute DFT component power ratios. A number of different frequency transform techniques may be employed, including Discrete Fourier Transform, Fast Fourier Transform, and Short-Time DFT techniques. One of several frequency transform approaches may be implemented depending on whether the detected airbearing signal is stationary or non-stationary. The airbearing resonance frequency methodology may be implemented in-situ a data storage system.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method, performed within a data storing system, of estimating a value of a resonance frequency of an airbearing associated with a slider flying in proximity to a data storage medium, the method comprising: obtaining a readback signal from the data storage medium; and estimating, in-situ the data storing system, the value of the airbearing resonance frequency using the readback signal.
2. The method of claim 1 , wherein estimating the value of the airbearing resonance frequency comprises estimating the value of the airbearing resonance frequency using the readback signal obtained from the data storage medium over a plurality of complete airbearing periods.
3. The method of claim 1 , wherein estimating the value of the airbearing resonance frequency comprises using spectral leakage associated with a frequency transform of the read back signal to estimate the value of the airbearing resonance frequency.
4. The method of claim 1 , wherein estimating the value of the airbearing resonance frequency comprises using a frequency transform of the readback signal, the frequency transform obtained using a Discrete Fourier Transform (DFT), a Fast Fourier Transform (FFT), or a Short-Time Discrete Fourier Transform (STFT) of the readback signal.
5. The method of claim 1 , wherein estimating the value of the airbearing resonance frequency comprises using a Discrete Fourier Transform (DFT) of the readback signal in accordance with Goertzel's algorithm.
6. The method of claim 1 , wherein estimating the value of the airbearing resonance frequency comprises: producing, using the readback signal obtained from the data storage medium over a plurality of complete airbearing periods, a discrete signal segment comprising a plurality of frequency transform components; and estimating the value of the airbearing resonance frequency using spectral leakage of the discrete signal segment.
7. The method of claim 6 , wherein the discrete signal segment is produced in response to detecting contact between the slider and a feature protruding from a surface of the data storage medium.
8. The method of claim 1 , wherein estimating the value of the airbearing resonance frequency comprises: producing, using the readback signal obtained from the data storage medium over a plurality of complete airbearing periods, a discrete signal segment comprising a plurality of frequency transform components; computing a ratio of a magnitude of a first component to a magnitude of a second component at each of a plurality of sampling rates, the second component related to the resonance frequency of the airbearing; and estimating the value of the airbearing resonance frequency using a minimum of the ratios.
9. The method of claim 8 , wherein the first component is a component adjacent the second component.
10. The method of claim 8 , wherein the first component is a non-adjacent component relative to the second component.
11. The method of claim 8 , wherein the sampling rates are defined by a number of samples per average airbearing period multiplied by a frequency defined within a range of expected airbearing frequencies.
12. The method of claim 8 , wherein the ratios are power ratios.
13. The method of claim 8 , wherein the readback signal comprises a magnetic signal component, a thermal signal component, or magnetic and thermal signal components.
14. The method of claim 1 , wherein the readback signal comprises a magnetic signal component, a thermal signal component, or magnetic and thermal signal components.
15. An apparatus provided in an enclosure for estimating a value of a resonance frequency of an airbearing, comprising: a data storage medium; a transducer provided on a slider and producing a readback signal obtained from the data storage medium; and a processor that receives the readback signal from The transducer and estimates, in-situ the enclosure, the value of the airbearing resonance frequency using the readback signal.
16. The apparatus of claim 15 , wherein the processor estimates the value of the airbearing resonance frequency using spectral leakage associated with a frequency transform of the readback signal.
17. The apparatus of claim 15 , wherein the processor estimates the value of the airbearing resonance frequency using one of a Discrete Fourier Transform (DFT), a Fast Fourier Transform (FFT), or a Short-Time Discrete Fourier Transform (STFT) of the readback signal.
18. The apparatus of claim 15 , wherein the processor estimates the value of the airbearing resonance frequency using a Discrete Fourier Transform (DFT) of the readback signal in accordance with Goertzel's algorithm.
19. The apparatus of claim 15 , wherein the processor estimates the value of the airbearing resonance frequency by: producing, using the readback signal obtained from the date storage medium over a plurality of complete airbearing periods, a discrete signal segment comprising a plurality of frequency transform components; computing a ratio of a magnitude of a first component to a magnitude of a second component at each of a plurality of sampling rates, the second component related to the resonance frequency of the airbearing; and estimating the value of the airbearing resonance frequency using a minimum of the ratios.
20. The apparatus of claim 19 , wherein the first component is a component adjacent to or non-adjacent to the second component.
21. The apparatus of claim 19 , wherein the ratios are power ratios.
22. The apparatus of claim 19 , wherein the readback signal comprises a magnetic signal component, a thermal signal component, or magnetic and thermal signal components.
23. The apparatus of claim 19 , wherein the processor varies a sampling rats of the discrete signal sample.
24. The apparatus of claim 19 ,wherein the processor estimates the resonance frequency of the airbearing using instructions contained in a signal-bearing media.
25. The apparatus of claim 15 , further comprising a detection circuit, the detection circuit detecting a change in an amplitude of the readback signal indicative of contact between the slider and a feature protruding from a surface of the data storage medium.
26. The apparatus of claim 15 , wherein the processor estimates the resonance frequency of the airbearing using instructions contained in a signal-bearing media.
27. The apparatus of claim 15 , wherein the readback signal comprises a magnetic signal component, a thermal signal component, or magnetic and thermal signal components.
28. A data storing system, comprising: a data storage disk; a transducer provided on a slider; an actuator for providing relative movement between the slider and the disk; and a processor that receives a readback signal from the transducer and estimates, in-situ the data storing system, a value of the airbearing resonance frequency using the readback signal.
29. The system of claim 28 , wherein the processor estimates the value of the airbearing resonance frequency using spectral leakage associated with a frequency transform of the readback signal.
30. The system of claim 28 , wherein the processor estimates the value of the airbearing resonance frequency using one of a Discrete Fourier Transform (DFT), a Fast Fourier Transform (FFT), or a Short-Time Discrete Fourier Transform (STFT) of the read beck signal.
31. The system of claim 28 , wherein the processor estimates the value of the airbearing resonance frequency using a Discrete Fourier Transform (DFT) of the readback signal in accordance with Goertzel's algorithm.
32. The system of claim 28 , wherein the processor estimates the value of the airbearing resonance frequency by: producing, using the readback signal obtained from the data storage disk over a plurality of complete airbearing periods, a discrete signal segment comprising a plurality of frequency transform components; computing a ratio of a magnitude of a first component to a magnitude of a second component at each of a plurality of sampling rates, the second component related to the resonance frequency of the airbearing; and estimating the value of the airbearing resonance frequency using a minimum of the ratios.
33. The system of claim 32 , wherein the ratios are power ratios.
34. The system of claim 32 , wherein the readback signal comprises a magnetic signal component a thermal signal component, or magnetic a thermal signal components.
35. The system of claim 32 , wherein the processor estimates the resonance frequency of the airbearing using instructions contained in a signal-bearing media.
36. The system of claim 28 , wherein the readback signal comprises a magnetic signal component, a thermal signal component, or magnetic an signal components.
37. The system of claim 28 , wherein the processor estimates the resonance frequency of the airbearing using instructions contained in a signal-bearing media.
38. A method of estimating a value of a resonance frequency of an airbearing associated with a slider flying in proximity to a data storage medium, the method comprising: obtaining a readback signal from the data storage medium; detecting a relative minimum in spectral leakage associated with a frequency transform of the readback signal; and estimating the value of the airbearing resonance frequency using the relative minimum in the spectral leakage.
39. The method of claim 38 , further comprising detecting a frequency component of greatest power of the frequency transform relative to other frequency components of the frequency transform using the relative minimum in the spectral leakage.
40. The method of claim 38 , wherein detecting the relative minimum comprises searching for the relative minimum in the spectral leakage.
41. The method of claim 38 , wherein: detecting the relative minimum in spectral leakage further comprises computing a ratio of a magnitude of a first component of the frequency transform to a magnitude of a second component of the frequency transform at each of a plurality of sampling rates, the second component related to the resonance frequency of the airbearing; and estimating the value of the airbearing resonance frequency further comprises using a minimum of the ratios to estimate the value of the airbearing resonance frequency.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
April 30, 2001
January 6, 2004
Browse 5M+ US patents with plain-English claim translations and AI-generated analysis.